Please help....

Hey, i have a 87' 325e, and today it stopped completly.... It has 79,000 miles on it, so that cant be the problem.... The battery is almost brand new... We jumped it 3 times, and the first two didnt get anything, the third time, we got maybe 1/4 a mile and it gave up... Do any of you guys know what could be wrong with it? And how much -for whatever the problem is- it would cost to repair? Thanks in advance...

When it cuts out does the engine still crank on full power,if not your alternator is not charging your battery for some reason,have charge rate checked,should be round about 13.5 to 14.5 volts.Good luck.

I say alternator too . . . .